Conivaptan for Treatment of Hyponatremia in Neurologic and Neurosurgical Adults

Abstract

To review the literature evaluating the clinical safety and efficacy of conivaptan in the management of hyponatremia in a neurologic and neuro-surgical adult patient population. A literature search was conducted using MEDLINE, EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials (1966-May 2013). Search limits were English, human, and adult using the terms vasopressin receptor antagonist, conivaptan, tolvaptan, lixivaptan, neurology, neurological disorder, neurosurgery, neurointensive care, and neurocritical care. All case reports, case series, and clinical trials investigating the use of conivaptan in neurosurgical patients were included. Seven reports were identified using conivaptan as monotherapy or adjunctive treatment for hyponatremia in a neurosurgical patient population. One study was a prospective, randomized, controlled trial, while 6 reports were case reports or case series. The prospective randomized trial found a significant increase in serum sodium concentration over baseline with a conivaptan 20-mg intravenous bolus dose followed by a 20-mg/day continuous infusion for 24 hours compared to "usual care" at 6 hours (7.0 ± 1.7 vs -0.6 ± 2.1 mEq/L, respectively; p = 0.008) and 36 hours (8.0 ± 5.6 vs -1.7 ± 2.1 mEq/L, respectively; p = 0.05) after treatment. One case series found that the mean serum sodium remained significantly increased from baseline up to 72 hours (5.12 ± 4.0 mEq/L; p < 0.001) after a single conivaptan 20-mg intravenous bolus dose. All reports demonstrated clinical effectiveness of conivaptan in significantly increasing serum sodium concentrations following administration compared to baseline. However, the clinical significance of this finding remains debatable since some of these patients remained hyponatremic. Overall, conivaptan is a promising and well-tolerated agent for the management of hyponatremia in neurologic and neurosurgical patients. However, its use should be limited to patients in whom conventional therapies fail or as adjunctive therapy.